In order to provide a cost effective, environmentally benign and efficient means for storing electric energy from renewable sources, breakthroughs are needed in rechargeable battery technology that will substantially increase energy and power densities. Practical deployment of the batteries for transportation also requires them to be of low cost and safe.
Organic radical batteries, ORBs, are a relatively new class of rechargeable batteries that are based on the utilization of stable organic radical molecular/polymer compounds as the cathode electrode within a high performance battery. The radical polymer electrodes can contain densely populated unpaired electrons in the pendant radical groups that are chemically stabilized via steric and/or pre-designed resonance effects. These stabilized radical systems are characterized by very fast electron-transfer processes that are the basis for the efficient performance of these systems in secondary batteries. These radical polymers are utilized as alternatives to inorganic metal-oxide or sulfur based materials as the primary cathode in the battery.
ORBs have several advantages over conventional batteries. ORBs are safer than conventional inorganic batteries because they are non-flammable, adaptable to wet fabrication processes, easily disposable, flexible and can be fabricated via “green” chemical processes. These high energy, safe, stable and “greener” systems also have extraordinary cycle life. The ORB is capable of several thousand deep (>80%) charging and discharging cycles at high rates/loads at full utilization of the capacity without performance loss (within 90% of initial performance). However, the major limitation for this technology is that the current charge storage capacity and specific energy of the present-day ORB is significantly lower than that of a conventional Li-ion battery.
The capacity of the most common ORB cathode active material is 110-130 mAh/g, which is less than the capacity of current cathode materials (150-170 mAh/g) in conventional Li-ion batteries. Therefore, there is a need for the design of and synthesis of new polymeric compounds with higher radical concentrations in order to significantly improve capacity and to make ORBS viable competitor for existing technologies. If achieved, ORBs will have an impact on technology and business from personal electronics to automobile to remote energy storage systems.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.